In an era of intensified market competition, internal brand management (IBM) has emerged as a critical strategy for aligning employee behavior with brand values. This study investigates how IBM influences brand citizenship behavior (BCB) among front-line restaurant employees in Macao, emphasizing the mediating role of brand identification (BI) and simultaneously testing the moderating effect of leader-member exchange (LMX). Drawing from Social Identity Theory and Social Exchange Theory, the structural equation modeling (SEM) was used to test the model using data from 315 employees across 11 Macao restaurant companies. Analyzing via software package Smart-Pls 4.1, we found that IBM significantly enhances BI, which in turn strongly predicts BCB. While IBM directly impacts BCB, the effect is mediated by BI. Furthermore, LMX moderates the IBM-BI relationships, underscoring the role of leadership in internal branding effectiveness. These findings contribute to the internal branding literature by validating BI as a key psychological mechanism and LMX as a boundary condition. Practically, the study provides insights for restaurant industry seeking to foster brand-aligned behaviors through internal brand management.